Various devices for repairing fluid leaks, particularly natural gas leaks, in various portions of pipes are known. U.S. Pat. No. 3,368,005 describes a device useful for repairing leaks in bell and spigot pipe joints. The device is wrapped around the joint and a sealant is injected into the cavity between the joint and the device. Gas in the cavity is said to be able to escape through a flap located where the two ends of the device overlap. The flap, however, prevents escape of sealant.
In order to determine when the cavity is full of sealant, some technique must be employed to monitor the pressure therein. Thus, for example, a pressure gauge may be utilized. Alternatively, the difficulty in pumping additional sealant into the cavity may be observed. Neither of these techniques is entirely satisfactory as they may give false indications of the amount of resin in the cavity.
Another such device is disclosed in U.S. Pat. No. 4,053,176. This device employs an inlet tube, a baffle or dam by the inlet tube, and a vent. The inlet tube is biased so that incoming sealant is steered in a desired direction. The baffle is placed in the direction of sealant flow to distribute the sealant across the width of the cavity to be filled. The inlet tube and the vent are located such that when the device is placed around the pipe joint, the inlet tube is located at or near the bottom of the joint and the vent is located at or near the top of the joint.
Locating the inlet in this manner is not satisfactory as it is difficult to reach and inject sealant therein. Moreover, no means is provided to prevent escape of unhardened sealant from the inlet. Consequently, it is necessary to insert some type of plug in it in order to prevent loss of sealant. This is cumbersome to do. Still further, the vent is open to the atmosphere and has no means to permit escape of sealant therefrom above a predetermined pressure. Conversely, it has no means to prevent escape below that predetermined pressure.